I think the 645E3A as put in the SD45X had very similar 'horsepower density' to the 3300hp version on a per-cylinder basis. If there were an engine-related problem other than one associated with longer crank, greater torsional stress, etc. the history of those locomotives might serve as a guide.
Since I'm unaware of significant engine issues with the Centennial's higher rating, one possibility is they thought it would be too slippery on a Geep. There's significantly more weight on each axle than your average GP40/GP40-2.
Doesn't explain though why it wasn't tried as a lower cost alternative to the SD45 and SD45-2. In particular, the extra 300 hp seems like it would've been a good fit for Union Pacific's high speed SD40-2's that were intended for high speed service alongside the Centennials.
As implied in other posts, the extra horsepower comes at a cost in the strain on various engine components. Earlier, EMD hit a similar maximum at 2500 HP in the 567 engine, and the 645 was developed to address that issue.
So, no one knows or can guess why the 3,300 HP "645" was not used in the SD/GP40's? Why put a 3,000HP engine in when you have a 3,300 HP engine? That's my real question, just phrased another way. I thought someone out there might have read something somewhere or heard something abot why.
Thanx. So EMD never used it in anything but the DDA40X?
Thanx for the info. Any idea (if the 3,300HP engine ran well in the DDA40x) why EMD might have tweaked it to 3,500 (ie..not just left it at 3,300HP)?
The SD/GP50's used the final tweak to the 645 with 3,500HP to the traction alternator. Reliability wasn't that great as the extra power required 950rpm from the 645 in run 8.
Just researched your question. The only other locomotive to use the 16-645E3A prime mover was the RENFE class 333 locomotives.
Can anyone speculate (or perhaps know) why the DDA40X "645" 3,300 HP prime mover was not used in the SD/GP40's (we all know that a "645" 3,000 prime mover was and has always been used for those locomotives)? Also, was the 3,300 HP engine ever used in anything other than the DDA40X?
Our community is FREE to join. To participate you must either login or register for an account.